1. Field of the Invention
The invention relates to a control of a vehicle equipped with an internal combustion engine and a vehicle-driving rotary electric machine. Specifically, the invention relates to a technology of consuming electric power generated by the vehicle-driving rotary electric machine, by using a heater device provided for heating a catalyst of the internal combustion engine, when the state of drive wheels of the vehicle changes between a slipping state and a gripped state.
2. Description of Related Art
In recent years, hybrid vehicles, fuel-cell vehicles, electric motor vehicles, etc. are drawing attention as a measure to curb environmental problems. With regard to such vehicles, there is a known technology of storing surplus electric energy that is generated when regenerative braking is performed via an electric motor, by an electricity storage device, or technology of absorbing surplus electric energy that is generated when regenerative braking is performed via an electric motor, by operating an accessory.
For example, Japanese Patent Application Publication No. 2005-002989 (JP-A-2005-002989) describes a motive power output apparatus that deals with a request for a braking force, which is made by turning off an accelerator pedal while taking into account a charging limit regarding the electricity storage device. The motive power output apparatus outputs motive power to a drive shaft, and includes: an internal combustion engine; electric power/motive power input/output means that outputs at least a portion of the motive power from the internal combustion engine via input and output of electric power and motive power; an electric motor capable of inputting/outputting the motive power to the drive shaft; electricity storage means capable of giving electric power to and receiving electric power from the electric power/motive power input/output means and the electric motor; an accessory that operates while consuming electric power that is produced from at least one of the electricity storage means, the electric power/motive power input/output means and the electric motor; control means for controlling the internal combustion engine, the electric power/motive power input/output means and the electric motor so that a requested drive force is output to the drive shaft; and accessory control means for forcing the accessory to operate regardless of the presence or absence of an operation command if it is predicted that the electricity storage means is to be charged with an electric power that exceeds a charge restriction of the electricity storage means by a control performed by the control means when a braking force on the drive shaft is requested by an action of reducing the amount of operation of an accelerator.
The motive power output apparatus described in the foregoing publication is able to output to the drive shaft a braking force that is requested via the action of reducing the amount of accelerator operation while taking into account the charge restriction of the electricity storage means. As a result, it is possible to restrain the deterioration of drivability in relation to the braking force requested via the action of the accelerator operation-reducing action while taking into account the charge restriction of the electricity storage means.
However, in the case where the drive wheels are changed between a slipping state and a gripped state, surplus electric power is suddenly and rapidly produced from the vehicle-driving rotary electric machine, giving rise to a problem in that the generated surplus electric power cannot be sufficiently consumed in good response. If the surplus electric power cannot be sufficiently consumed, it may hinder the battery from delivering its full performance.
The motive power output apparatus described in the foregoing publication operates an air-conditioner compressor in order to consume the surplus electric power that is produced during regenerative braking. An air-conditioner compressor is able to consume electric power as the rotation speed of an electric motor provided in the air-conditioner compressor increases after supply of electric power to the electric motor is started. Therefore, since the electric power that can be consumed is limited when the rotation speed of the motor is low, the air-conditioner compressor is not able to highly responsively and sufficiently consume the surplus electric power that suddenly occurs.
In addition, although it is conceivable to provide a discharge resistor that is mainly intended to consume surplus electric power, this will increase the number of component parts, and may become a factor of cost increase.